1. Field
Aspects of the exemplary embodiments relate to methods of manufacturing semiconductor devices, and more particularly to methods of manufacturing complementary metal oxide semiconductor (CMOS) transistors.
2. Description of the Related Art
Semiconductor manufacturing technologies have been developed to improve mobility of carriers by providing stress to a channel region of a transistor. Specifically, a compressive stress may be provided to a channel region of a positive metal oxide semiconductor (PMOS) transistor to improve mobility of holes and tensile stress may be provided to a channel region of a negative metal oxide semiconductor (NMOS) transistor to improve mobility of electrons.
For example, carbon atoms may be ion-implanted to a source/drain region to provide the tensile stress to the channel region of the NMOS transistor. However, the carbon atoms may be inactivated by a subsequent thermal or heat treatment so that the tensile stress provided to the channel region may be reduced.